The instant invention relates generally to silo unloader apparatus. More particularly, the present invention relates to apparatus for automatically facilitating the orderly positioning of a silo unloader output chute during a silo unloading operation.
At present a variety of prior art silo unloader apparatus is employed in the agricultural arts. Most of these comprise a base portion adapted to be centrally disposed within the silo overlying the silage therewithin. A rotatable auger assembly coupled to the base revolves within the silo, thereby picking up silage. The auger assembly communicates with a discharge chute through which silage is forced by blower apparatus. The discharge chute must of course be properly aligned with respect to the silage discharge orifices provided in the silo in order to facilitate the passage of silage therethrough. As the auger assembly continuously rotates and picks up and discharges silage, the vertical position of the silage unloading apparatus will continually recede. Known prior art silage unloaders are disclosed in U.S. Pat. Nos. 2,963,327, issued Dec. 6, 1960; 3,002,790, issued Oct. 3, 1961 to G. Chapman; 3,539,059, issued Nov. 10, 1970; 3,698,575, issued Oct. 17, 1972; and 3,065,033, issued Nov. 20, 1962. Each of the latter references include some form of chute positioning apparatus relevant to the torque arm assembly described herein.
Of course when most silo unloaders of the latter type are employed, the discharge orifice doors must be opened at an appropriate time. One type of door for blocking silage discharge orifices is described in my co-pending patent application entitled "Automatic Silo Door System," filed July 29, 1976, Ser. No. 709,935, now U.S. Pat. No. 4,071,977 and owned by the same assignee as in the instant case.
As the level of silage decreases during the unloading operation the silage discharge chute must be repositioned relative to a lower silage discharge orifice. Chute repositioning is usually done manually with prior art devices. Most silo unloader torque arm assemblies have some portion received through the silage discharge orifices to track within same. However, no known prior art silage discharge apparatus includes means for automatically, sequentially engaging silage discharge orifices while specifically limiting the dropping distance of the torque arm apparatus to an increment of the discharge orifice height.